Fluorescent tubes such as CCFL have been conventionally used as a light source for liquid crystal display devices that are incorporated in devices such as TVs, in-board car navigation systems, and instrument panels. Recently, a white LED which has an extremely high brightness has been developed; replacement of the CCFL by the LED is now under consideration. This white LED, in order to achieve the high brightness, has a surface which reflects light emitted from an LED chip. In many cases, an Ag layer is formed on this surface by plating or vapor deposition of Ag that has an extremely high light reflectance of visible light (not less than 90%).
Regarding such an LED, Patent Literature 1 discloses a technique which attains a high refractive index in sealing resin of an LED chip, while suppressing a decrease in reflectance of a reflecting electrode caused by generation of a sulfide. Patent Literature 2 discloses a technique in which an optical sheet (for example a prism sheet) to be used in a liquid crystal display device or the like achieves both a high refractive index and elimination of a halogen, which elimination is for not adversely affecting the environment.